Automatic telephone system



W. T. POWELL.

AUTOMATIC TELEPHONE SYSTEM APPLICATION FILED JULY :9, m5v

1,303,958. Patented May 20, 1919.

W. T. POWELL.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED JULY 19. I915.

Patented May 20, 1919.

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m. wasmmnou a c W. T. POWELL.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION mm JULY I9. 1915.

Patented May 20, 1919.

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UNITED STATES PATENT OFFICE.

WINFRED T. POWELL, OF CHICAGO, ILLINOIS, ASSIGNOB TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Application filed July 19, 1915.

T 0 all whom it may concern Be it known that I, \Vixrunn T. PmvnLL, a citizen of the United States of America. and resident of Chicago, county of Cook, and State of Illinois, ha ve invented certain new and useful lmprovenwnts in Automatic Telephone Systems, of which the following is a spccification.

My invention. relates to automatic telephone systems and more particularly to those systems which comprise a plurality of exchanges between which connection may be established automatically by the individual subscribers. A common method of fixing the amount to be charged for service in these systems is to provide each subscribens line with a. registering device or meter which will register once for each successful originating call. The subsrribeik meter may be so arranged that it will not register on calls to a certain class of subscribers such as oflicials oi" the telephone company, etc, but ordinarily it cannot discriminate between any of the calls that are to be charged, 1". 6., it either registers or it does not register.

Now in systems where the exchanges are widely distributed it is often desirable to make a. small toll charge between certain exchanges the amount usually depending on the distance between the points connected. For example, consider three automatic exchanges A, B and Subscribers at A may call other subscribers in the same o-ilice for the minimum amount. which may be five cents. For connection between A and B, if ii is located at some distance from A, it may be desirable or ncce; airy to charge an amount in excess of the minimum; likewise for connections between. A and 0 it may be desirable to charge a still greater amount.

Heretolore it has been the practice to restrict the automatic calling to those exchanges which lie within a comparatively lo *al area. If the systems contain outlying exchanges or ofiicesn the subscribers are not allowed to connect with such exchanges automatically but are required to call a checkingoperator and notify her of the connection desired. The operator is provided with suitable means for extending the connection to the desired party and is expected to record the name and number of the calling party together with the amount to be collected for the call.

Specification of Letters Patent.

Patented May 20, 1919.

Serial No. 40,704.

Efforts have been made in the past to devise means for automatically collecting the charges to exchanges having different rates but so far as known these efforts have not been entirely Successful.

The object of my invention is the provision of a new and more practicable method of automatically charging for calls having dilferent rates. In my improved system the digit oi the called number which determines to which exchange the connection is to be extended also determines the amount of toll to be charged. I employ no apparatus at the subseribefis station other than the regular automatic telephone but prefcra bly use so called meters individual to the subscribers lines and located at the exchange. I provide simple and eliicient means at each exchange for actuating the. meter of a calling subscriber a 'ariable number of times depending on the exchange to which con nection was extended. For example if connection is made with a subscriber in the same or nearby oflice the meter will be actuated once. If, however, a call is made to a point which carries an additional charge of ten cents the meter will be actuated three times. It is apparent that in this manner various amounts may be registered by suitable actualtions oi the subscribers meter. I desire to explain that while the metering in my system is entirely automatic when once started it will not begin to register until started by an operator in the distant exchange. I provide means by which a supervising operator may listen in on the incoming trunks at the proper time, as indicated bv a lamp signal, to ascertain whether or not the answering party is the one wanted. It the call is successful the operator will press for an instant a button associated with the signal lamp. Th is starts the mechanism in the originating oiiice which proceeds to actuate the meter the required number of times as determined by the first digit of the called number.

Having briefly described. the object and scope of my invention I will now proceed to a more detailed description of the same, reference being had to the accompanying drawings.

In the drawings, Figures 1, 2 and 3 show a complete connection between a calling substation A and a called substation A located in separate exchanges in an automatic system embodying the principles of my invention. That portion of the apparatus which is peculiar to my invention is shown in Fig. 2, the remaining parts being well known in the art, and included only in order to more clearly show the operation of my improve ment.

At A there is represented an automatic substation to the line conductors of which there is allotted at the central office an individual or line switch C. At D there is shown a master switch for controlling a group of the switches C. The line switches of this group have common access to a number of trunk lines which lead to first selector switches E. A number of first selectors have common access to a group of repeaters It. Each repeater is connected to a trunk line L L extending to a distant exchange where the line terminates in a second selector F. A number of second selectors have common access to a group of connectors H by means of which connection may be completed with subscribers lines. At S is shown a rotary switch associated with the repeater R. At P are shown the essentials of a supervising operator's position in the distant exchange. At B is shown a battery having one terminal grounded and at B, a second battery also having one terminal grounded. Associated with each snbscribefis line is a me.- ter M.

The substation shown herein may be of any suitable or approved type and comprises the usual receiver 2, transmitter 3, ringer 1 and condenser 5. Being an automatic substation it is also provided with an impulse transmitter or calling device, which is represented herein by a pair of impulse springs 6 and 7 and an impulse wheel 8, which latter is assumed to be controlled through the medium of a finger hole dial (not shown) in such a manner that the impulse springs 0 and 7 may be momentarily separated a number of times corresponding to each digit of the called number.

The line switch C. which is associated with the line of substation A. is of the general type of line switch shown in British patent to R. James No. 26,301 of 1006, which is well known in the art. This line switch comprises .among other details a plunger (not shown) attached to the end of a so called plunger arm 14 which is controlled by the magnet 13. The magnet 13 comprises two windings, the pull-in winding 18 and the holding or cut-off winding 17. The winding 18 operates both the plunger arm 14 and the cutofl armature 15, while the winding 17 is only strong enough to operate the armature 15 and to hold the plunger arm 1-1 in an operated position after it has once been operated by the pull-in winding 18. The circuit of the pull-in winding is controlled by the line relay 12, which is slow acting, 2'. (1., it retains its arm-(c ture for an instant after the energizing circuit is broken. When the plunger arm 1-1 is operated, the plunger is forced into a bank of springs, forcing the springs 27, 28, 29, 30 into engagement with the contacts 31, 32, 33, 3-1, respectively. Although only one set of springs and contacts (273'-'l) is shown, it is to be understood that each line switch is provided with a plurality of such sets, each set forming the terminal of a trunk line leading to a selector switch E. Each trunk line is connected in multiple to the corresponding springs of all the switches of the roup which is controlled by the master switch D.

The master switch D is of the same general type as that disclosed in British patent to Ix. W. James No. 26,301 of 1900, above referred to, being, however, more nearly of the particular type disclosed in Britsh pat ent to T. G. .Martin No. 1410 of 1910. The function of the master switch, as is well known, is to maintain the plungers of all the idle line switches in position before an idle trunk line.

The selector E is of the general type of selector disclosed in ll. 5. Letters Patent No. 815,321 granted March 13. 1000, to Keith, Erickson and Erickson, the circuits being modified in order to operate in a system in which the impulses are delivered over both sides of the line in series. Among other details, the selector E comprises a set of wipers r8, (9 and 80 carried upon a. vertically and rotatably movable shaft (not shown). The shaft is actuated in its vertical movement by the magnet 16 and in its rotary movement by the magnet 17. The selector is controlled by means of the line relay 40. Means for permitting the switch shaft to be restored to normal position are provided in the release magnet 12, which, upon energizing, withdraws the retaining pawls from the shaft. The springs 75 are permitted to close only when the switch shaft has been raised one or more steps from its lowest position. The relays 41 and -13 are slow acting, i. 6., they will retain their armatures for an instant after the energizing circuit is broken.

The repeater R has no moving parts but consists simply of relays mounted in any suitable manner. Relays 102 and 101 are slow acting, i. 6., their armatures are retained for an instant after the energizing circuit is broken. Relay 103 is a polarized relay, the winding 101 being the polarizing winding. The winding 104 is of German silver wire and does not energize the relay sulficiently to enable it to attract its armature. (loils 106 and 107 are balancing coils whose purpose will be explained later.

Associated with each repeater is a rotary switch S which may be of any suitable construction the only requirements being that it consist of tWo separate sets of contacts and wipers for each set, such Wipers being continuously in contact with at least one of the contacts in their respective sets, and adapted to be rotated by a suitable motor mechanisn'i. As shown diagralmnaticz-llly in Fig. 2, the two sets of contacts or banks form each an arc of one third of a circle and there are three multiple wipers for each bank spaced at an angle of from each other so that as one of the wipers leaves the last contact of its bank a multiple wiper will ride up on the first contact. The contacts 139 are all connected to ground at G except the first contact whi h is the one upon which wiper VV' or its multiple wiper normally rests. In the other bank the 1st. 3rd, 5th, etc.. contacts are marked 138 and are multipled together and connected to ground at G". The alternate contacts are marked 137. A certain number of these alternate contacts 137 are multipled together and connected through the resistance r with the positive pole of battery B. The remaining contacts 137 are nnlltiplcd together and (011 nected to ground at G".

Connection is made for talking purposes with the trunk lin L L by means of the re peating coil R and at the distant end by means of the repeating coil R Impulses are transmitted over the two sides of the trunk line in parallel forming what is commonly known as a simplex circuit.

The supervising operators position P is equipped with listening jacks J, lamps 1, and keys K.

The second selector is of the same general type and construction as the first selector already described. The line relay 140 of the second selector is energized over a circuit closed by the relay 186 which in turn is en ergized by impulses over the simplex circuit. The relay 193 is a polarized relay similar to the relay 103 of the repeater R.

The connector H is of the same general type and construction as that disclosed in U. S. Letters Patent No. 815,176, granted March 13, 1906 to Keith, Erickson and Erickson. the circuits, however, being modifield to enable the switch to operate in a system in which the impulses are delivered over the two sides of the line in series. It has the usual magnets for raising and rotating the shaft and for efi'ecting the release of the same. The private magnet 245 controls the movement of the side switch wipers 252, 253. 254 and 255. The usual back bridge relay 249 feeds talking battery to the called line. and when energized, reverses the incoming lines from the second selector. A ringing relay 251 is also provided which is energized at the proper time in series with the interrupting commutator I and operates to send ringing current over the called subscribefis line from the generator 281.

Having given a general description of the apparatus, I will now describe the operation of a system embodying the principles of m invention. It will be explained how a subscriber at A may complete an automatic connection with a subscriber A in a distant exchange whose toll rate is assumed to be fifteen cents. It will also be explained how the subscribers meter M will be actuated three times to register such a connection, the actuation of the meter being accomplished automatically in response to an initial impulse from the distant exchange. Further, it Will be shown how the calling subscriber can bring about the restoration of the apparatus to normal at the termination of the conversation.

In connection with this description it is to be understood that in Innlti-olficc systems such as the one under consideration certain of the selector levels in each exchange contain terminals of trunks leading to the other exchanges. lhcsc trunks may terminate either at first selector levels or at second selector levels depending on the size of the exchange to which they lead. In the present case it will be assumed that the trunks leading to the exchange to which A is connected tern'iinate in first selector levels at the exchange towhich A is connected and I have arbitrarily assigned the fifth first selector level to these trunks although any other level would have served equally as well. Then it follows that the first digit of As telephone number must be 5 since to reach the fifth level the figure five must be called. The remaining digits of As number are determined by the location of his individual switch in the exchange to which he is connected and will be assumed to be 678. Then his entire number will be 5678.

When the. subscriber at A. in making the call, raises the receiver from the hook. a circuit will be completed for the line relay 12 ot' the line switch C. said circuit extending from ground at G, through normally closed springs 22 and 21, over line 11 to substation A from whence it returns over line 10, through normally closed springs 20 and 19, winding of line relay 12 to battery. Upon the energization of the line relay a circuit for the pull-in winding 18 of the line switch C is closed as follows: ground at G armature 24, contact spring 23. pull-in winding 18, to battery at contacts and 26. Upon the energization of the pull-in winding the plunger arm 14.- and also the armature 15 are attracted, the former by means of its plunger, causing the springs 27-430 to make connection respectively with the contacts 3134, and the latter breaking the connection of the springs 19 and 21 with the springs 20 and 22 respectively. The closing of the bank contacts 27 and 31 and 30 and 34 Completes a circuit for the line relay l0 of the selector is as follows: ground at G, winding 49 of the line relay l0, normally closed contact springs 66 and 65, bank contacts 3% and 30, through the subscribers loop, bank contacts 27 and 31. normally closed contacts 62 and (33. winding of the line relay 10 to battery. When line relay l0 attracts its armature it closes a circuit for slow acting relay -11 as follows: ground at G. working contacts 56 and .37. winding of relay 41 to battery. Relay l1 in turn closes a circuit for the holding winding 17 of the line switch as follows: ground at G contact springs 51 and 50, back contacts 32 and 28, holding winding 17 to battery. Although the circuit of the slow act ing line relay 12 has already been opened by contacts controlled by the armature 15 it holds its armature 2i attracted long enough to enable the above described holding circuit to take elfect and so retain the arm 14 and the armature 15 in operative position.

It will be noticed that a branch of the holding circuit passes through the meter M but the current flow is not sutlicient to operate the meter at this time. A second branch of this circuit extends to the test contacts of the calling line and makes it busy to incoming calls.

Now when the. subscriber at A dials the first digit 5. of the number he wants he breaks the continuity of his loop fivo times which causes the line relay -10 of the first selector E to retract its armature a corresponding number of times. As a result a circuit for the vertical magnet 46 which was prepared and is maintained by the slow acting relay 41, is completed as follows: ground at G, contact springs 56 and 55, normally closed contacts 67 and 68, working contacts 53 and 52, Winding of relay 43, winding of vertical magnet l6 to battery. This circuit. being closed five times by the retrartions of the line relay armature, the vertical magnet operates five times to raise the. switch shaft five steps, when the line wipers will be raised to the level assigned to the distant ofiice to which A. is connected. At the first vertical step the off normal. contacts 74 and 7 5 are closed. Contact closes a circuit, for the release magnet 42 which for the present is open at contact springs 53 and 5% of relay 41. Contact 74 prepares circuits which will be described. Relay 43 is in series with the vertical magnet and is energized intermittently during the, vertical impulses. Since relay 43 is slow acting it retains its armature in an operated position during the series of impulses thereby closing a circuit for the private or test relay 15 as follows: ground at G. contact springs 58 and 59. winding of relay 45 to battery. Relay 45 closes a locking circuit for itself as follows: ground at G", contact springs 51 and 50, contact 72, otf normal contact 74. contact ning TU and (it), winding of relay 45 to battery. A branch of this circuit also extends from contact springs 69 to the rotary magnet t? but remains open for the present at contact springs 59 and 60. A testing circuit is also completed to the private or test wiper 79 by the contacts 69 and 70 and will be described. Now at the end of the series of impulses the relay 43 becomes permanently deiinergizcd and retracts its ar mature thus closing the circuit already prepared forthc rotary magnet as follows: ground at G. contact springs .71 and 50, contact 72, off normal contact H, contact springs 70 and (39, contact springs 59 and (30, contact 73. winding i7 of rotary magnet to battery. The rotary magnet attracts its armature 76 and rotates the shaft one step so that the wipers T8, 79 and make connection with the first set of contacts of the fifth level. Near the end of its stroke the armature 76 opens the contacts 72 and 73 thereby opening the circuit of the rotary magnet and the locking circuit of the test relay 4-5. The rotary armature accordingly falls back but the deenergizution of the test relay 45 depends on the condition of the test contact upon which the private wiper 79 is now resting. if the trunk with which this test circuit is associated is busy. the test contact will have ground potential upon it and a holding circuit for the test relay 4:5 will exist as follows: ground on test contact, private wiper 79. contact springs 70 and 69, winding of test relay 45 to battery. Then the test relay will remain energized and as the rotary armature returns to normal position and closes the contacts 72 and 73 the rotary magnet will again be energized and will move the wipers i8, 79 and 80 into connection with the second set of contacts of the fifth level. In this manner the wipers will continue to be rotated until they reach an idle trunk as indicated by the absence of ground on the. test contact.

The test relay l5 will then fall back and the wipers 78, 79 and 80 will be brought to rest on the contacts of the trunks selected, represented at 81. S2 and 83. Then the test relay 45 dei nergizcs it closes a circuit for the line switching relay is as follows: ground at G, contact springs 51 and 50. contact 72, off normal contact 74, contact springs 70 and 71, winding 414 of line switching relay to battery. On attracting its armature, the line switching relay completes a circuit for the line relay of the repeater R- as follows: ground at G, winding 109 of line relay 100, winding of repeating coil R bank contact 83, wiper 80, contact springs 6i and 65, bank contact 34, spring 30, subscribers loop and instrument A. spring 27. bank contact 31, contact springs 62 and 61, wiper 78 bank contact 81, Winding of repeating coil R, winding 108 of line relay 100 to battery. The line relay 100 attracts its armature and closes a circuit for the slow acting relay 101 as follows:

ground at G, contact springs 111 and 112, winding of slow acting relay 101 to battery.

T be slow acting relay closes the following holding circuit: ground at G", multiple contact 138 of the rotary switch S, wiper W, contact springs 117 and 118, bank contact 82, wiper 79, to spring at which point the circuit divides, one branch extending by wayof sprin 71, and winding 44 of the line switching re ay to battery, and the other branch extending by way of off normal contact 74,: contact 72, bank contact 732, spring 28, and winding 17 of the line switch to battery. VVhen the line switching relay 44 was energized it opened the circuit of the line relay 40. The line relay then deiincrgized and. opened. the circuit of the slow acting relay 41 which, however, held its armature attracted for an instant in order to give the new holding circuit described above time to be completed at the repeater R. The line switchin relay also opens the release circuit which is prepared by the falling back of the line relay and the slow acting rel'ay 41.

We have now established connection with the repeater R which terminates in a trunk line leading to the distant exchange. The line relay of the repeater is energized in series with the subscribers loop and in turn closes the energizing circuit of the relay 101 in a manner previously described. The slow acting relay 101, in addition to closing the holding circuit, prepares a circuit for the slow-acting relay 102 and also closes a circuit for the polarized winding 104 of the polarized relay 103 as follows: ground at G, contact springs 120 and 119, winding 104 to battery. The winding 104 is of high resistance and comparatively few turns and therefore does not magnetize the coil 103 sulliciently to enable it to attract its armature.

I will now describe a circuit which has been completed by the line relay for sending impulses to the distant ollice: ground at G, windings 187 and 188 of relay 186 in series, windings W and W of repeating coil R in parallel, lines L and L in parallel, windings and W of repeating coil R in parallel,'balancing coil 106, contact springs 114 and 113 tobattery. This circuit is in parallel with another circuit as follows: ground at G, adjustable resistance 1', balancing coil 107, contact springs 114 and 113 tobattery. The winding 105 of the polarized relay 103 is bridged across the two arallel circuits as follows: One terminal 1s connected to the junction of balancing coil 106 with the middle point of the repeating coil winding, the other terminal is connected to the juncimpulses.

tion of balancing coil 107 with adjustable resistance 1".

It is apparent that the combination of the two parallel circuits with the winding 105 properly bridged between them as described and shown in Fig. 2 forms an arrangement similar to the well known Wheatstone bridge; and it will be shown at the proper time how, by destroying the normal balance of the bridge, current is made to flow in the winding 105 in the proper direction to operatively energize it.

When the impulse sending circuit previously described was closed at the line relay 100, the relay 186 at the distant ofiice was energized and by attracting its armature, closed the following circuits: ground at G, contact springs 190 and 189, polarizing Winding 194 of polarized relay 193 to battery; ground at G, winding 149 of line relay 140 of second selector F, contact springs 106 and 165, winding W of repeating coil R contact springs 191 and 192, winding 195 of polarized relay 193, winding of repeating coil R", contact springs 162 and 163, winding 148 of line relay 140 to battery. The line relay 140 is energized over the latter circuit and in turn closes a. circuit for the slow acting relay 141 in a manner already described in the ease of the first selector E. The winding 195 is so connected that when the current flows through it in the direction described, its magnetizing effect will oppose that of the winding 194 and therefore the relay 193 will remain inoperative.

The subscriber at A may now rotate his dial for the second digit of the desired number, thereby breaking the circuit of the line relay 100 of the repeater R six times. The line relay 100 in turn opens the circuit of the relay 186 at the distant oflice a like number of times, resulting in six interruptions of the circuit of the line relay 140 of the second selector F. The line relay of the second selector controls the circuit of the vertical magnet in the well known manner which operates to raise the shaft of the second selector to the sixth level, when it is automatically rotated until the wipers arrive at an idle trunk line leading to a connector switch H. The circuits and operation of the second selector are similar to those of the first selector already described; consequently, this description need not be repeated. It should be understood, however, that the second selector banks are terminals of trunk lines leading to connectors while the first selector banks are terminals of trunk lines leading to repeaters or to second selectors.

It is well to return here to the repeater R and trace several circuits resulting from the deiinergization of line relay 100 during At each retraction of the armature a circuit is closed as follows: ground at (W. contact springs 111 and 110, contact springs 115 and 116, winding of relay 102 to battery. Slow acting relay 102 is energized and places a shunt around the balancing coil 106 and since the slow acting relay does not lll'll'lltKllZlbOlY retract its armature when deenergized, it maintains this shunt during the series of impulses. The purpose of this shunt is to decrease the resistance and im pcdance of the impulse circuit. Now when the balancing coil 106 is shunted out it will be evident at once that the balance of the Wheatstone bridge will be destroyed and current will flow in the winding 105 of the relay 103. The path of this current is as follows: ground at G adjustable resistance r. winding 105 of polarized relay 103, contact springs 122 and 121, contact Springs 114 and 113 to battery. The winding 105 is so connected, however, that current flowing in the direction described above produces a magnetizing effect in opposition to that produced by the winding 104 and, therefore, the polarized relay 103 remains inoperative at this time.

The operation of a connector of: the gen eral type shown herein is well known and since it forms no part of my invention only a general description will be given.

The subscriber at A operates his dial for the third digit 7 of his number, and thereby opens the circuit of the line relay 240 of the connector H, seven times. The relay deenergizes a like number of times and energizes the vertical magnet 246 and slow acting re lay 243 in series, thereby raising the shaft of the connector until its wipers are opposite the seventh level of bank contacts. At the end of the series of impulses the slow acting relay 243 deencrgizes and breaks the circuit of the private magnet allowing the side switch wipers to move to the second position. The subscriber at A may now operate his dial for the fourth and last digit of his number, which is 8, and thereby breaks the circuit of the line relay 240 eight times. In response to the impulses the line relay deenergizes a corresponding number of times and energizes the rotary magnet and slow acting relay 243 in series, rotating the shaft until its wipers rest upon the eighth set of contacts of the seventh level which are the terminals of the line 5678 to which A is connected. At the end of the series of impulses the slow acting relay 243 and the private magnet 245 denergize as before, allowing the side switch wipers to move to the third position. (Assuming the called line to be idle.)

In the third position, the private wiper 201 of the connector is grounded at the side switch wiper 255. This ground extends over the private normal to the holding winding 270 of the line switch C and energizes it to attract the armature 274, thereby disoon necting the line relay winding 272 from the called line. Also the ringing relay 251, in series with battery and ground through the interrupter l, operates intermittently to send ringing current over the called subscribers line. A back bridge relay 249 is bridged across the called line in series with the battery, in order to feed talking battery to the called subscriber.

When the subscriber at A takes off his receiver in response to the ringing of his bell, he closes the circuit of the back bridge relay, which attracts its armature and closes the circuit of the ring out off relay 250.

Also by means of spring contacts 275, 276, 277, and 278, 279, 280 the back bridge relay reverses batter connections to the line of the calling subscriber. This reversal of the direction of current flow in the line has an important result which will be described in detail later.

Connection has now been completed be tween a subscriber at A in one exchange and a subscriber at A in a distant exchange and conversation can be carried on without further effort on the part of either subscriber. It only remains to be seen how the meter M of the alling SllbFlClllJOI' A shall be actuated a number of times corresponding to the toll rate to the distant office ssumed in this case to be fifteen cents.

Returning to Fig. 2 it will be remei'nbercd that the polarized relay 193 was inoperative because the magnetizing effects of its two windings opposed each other.

Now when the back bridge relay of connector l-l pulls up it reverses the direction of current flow in the winding 195 of the polarized relay 193.

The two windings of the relay 193 now assist each other and it at once attracts its armature closing the following circuit: ground at G contact springs 196 and 197, lamp 1 to battery. The signal lamp 1, with similar lamps associated with other incoming trunks, is mounted in front of a supervising operator whose duty it is to listen in on an incoming trunk in response to the lighting of the associated lamp and ascertain whether or not the call was successful. If the party answering proves to be the party wanted the supervising operator presses her key K, associated with the trunk in question and has nothing further to do with the connection. The key K short circuits the high resistance winding 187 of the relay 186. The winding 188 is of low resistance having only enough turns to enable the core 186 to keep its armature attracted.

It has been explained before how the line L L in series with the two windings of the coil 186 formed one leg of a Wheatstone bridge. When therefore, the winding 187 is short circuited by the key K, the normal balance of the bridge will be destroyed and current will flow in the winding 105 m the polarized relay 103 over the following path: ground at (1' contact 108, winding 188, windings VW and \V of repeating coil 1F in. parallel. wires L and T1 in parallel, windings il and l of repeating coil It in parallel winding 105 of polarized relay 105, balancing coil 107, contact springs 11* and 113 to battery. The current flowing in the direction described above produces a magnetizingcil' i't which strengthens the magnetism due to the current in the l'iolarizing winding 104, and the armature is attracted closing the following circuit ground at G, contact springs 123 and 124, winding of relay 130 to battery. 'lelay 130. upon energizing, prepares a. locking circuit for itself by spring contacts 135 and 136, and also closes the following circuit for the motor magnet 131 of the switch S: ground at G, interrupter I, contact springs 133 and 134, winding of motor m'agnet 131 to battery.

The motor magnet 131. under the influence. of ground impulses from interrupter I alternately attracts and detracts its armature, thereby causing the wipers 1V and V to sweep over their respective bank contacts. At the first step the wiper 1V comes on to the first grounded contact 139 and completes the locking circuit for relay 130 as follows: ground at G, contact 139, Wiper VV', contact springs 135 and 136, winding of relay 130 to battery. Also at the first step the wiper W leaves the first grounded contact 139 and makes connection with the first contact 137 which is connected to the positive pole of battery B. In a circuit already described it has been shown how the subscriber As meter M was connected in parallel with the holding coil 17 of the line switch by means of the contact 16. It has also been stated that the current flowing from ground at G" over the holding trunk and through the meter M was not suflicient to energize it. Now when the wiper arrives at the first contact 137 the holding trunk is disconnected from ground at G" and connected to the positive pole of battery B thus connecting the two batteries B and B in series and causing an increased current to flow through the meter over the following path: ground at G through battery B, resistance r, contact 137, wiper W, contacts 117 and 118. back contact 82. wiper 7!), off normal contact Tl. contact 72, bank contact 32, spring contact 28, winding of meter magnet 35, contact 16. to battery B and ground at G This strengthened current is sufficient to operate the meter M and it registers once. As the wipers and W continue to sweep over their banks of contacts it will be readily understood that the meter M will be actuated every time the wiper ll encounters a contact 137 connected as described to battery B. It is only neccs sary then to connect as many of the contacts 137 to battery B as there are desired actuations of the meter M. The particular group of repeaters of which R is one would all have three contacts 137 in their respective switches S connected to battery B. The fourth contact 137 and all remaining con tacts would be connected to ground as shown in order not to interrupt the holding trunk circuit. As the wipers continue to rotate the wiper W will e'vei'itually leave the last contact 139 and its multiple wipcr will arrive at the first contact 13!). The first contact 139 is ungrounded and therefore the locking circuit of the relay 130 will be broken and it will detract its armature thereby breaking the circuit of the motor magnet 131 and the wipers \V and V will be brought to rest in their normal position.

It is apparent. that a second group of repeaters similar "to R and terminating in trunk lines leading to an exchange whose toll rate is twenty five cents. would have, live contacts in banks of the corresponding switches S. connected to battery l3. In the same manner another group of repeaters It might have but one contact in their switches S connected to battery 3 thus providing for but one actuation of the -alling subscriber's meter. In any case when the calling subscriber pulls the first digit of his number he selects a group of repeater. terminating in trunk lines leading to the desired exchange and whose associated switches :4 have a certain number of contacts 137 connected to battery B. the number of contacts so connected depending on the toll rate to the desired exchange.

I will now describe how the subscriber at A, having finished his conversation. accomplishes the disconnection and restoration to normal of the apparatus in use.

Vi hen the subscriber at A places his receiver upon the hook the circuit of the line relay 100 is broken. On detracting its armature line relay 100 opens the circuit of the slow acting relay 101 which in turn breaks the holding circuit of the line switch 0 and of the line switching relay H of the first selector. Upon the dei nergization of the holding winding 17 the plunger arm 14: withdraws the plunger from the bank thereby separating the spring contacts 27, 28, 29, 30 from the bank contacts 31, 32, 33 and 34. Also the line switching relay 4% closes an energizing circuit for the release magnet of the first selector upon dei nergizing. the release magnet withdraws the retaining pawls from the shaft allowing it to return to normal when the circuit of the release magnet is again broken at contact 75. IVhen line relay 100 dccuergizcs it also breaks the circuit of the relay 186 in the distant office. Upon decnergizing the relay 186 breaks the circuit of the line relay 240 of the connector H. The line relay in turn breaks the circuit of the slow-acting relay 241 which. upon deenergizing opens the holding circuit of the relay 144 of the second selector I and also closes the circuit of the release magnet 1212 of the connector II. Bo h second selector and connector are then returned to normal in a manner already described in the case of the first l0 selector. L

VVhih I have described one form in which my invention may be practised I do not Wish to be strictly held to the form shown herein. but desire rather to include all modifications which may come Within the scope of the appended claims.

What I claim as my invention is:

1. In a telephone system. a toll assessing! device. means for controllii'ig said device. a

heatstone bridge. and other means for unbalancing said bridge for controlling said device through the medium of said first means.

2. In a telephone system. a toll asses-ling 2 device, means for controlling said device. a

Vi heatstonc bridge, other means for unbalancing said bridge for controlling said device through the medium of said first means. said first means including a circuit for said device. a source of potential in said circuit, and a source of potential for boostiug the first potential in said circuit to control said device.

3. In a telephone system. a toll assessing device. means for controlling said device. a

Wheatstonc bridge, other means for unbalancing said bridge for controlling said. device through the medium of said first means. said first means including a circuit for said device. a source of potential in said circuit. a source of potential for boosting the first potential in said circuit to control said device, and an impulse sender for controlling the application of said booster potential to said circuit.

4. In a telephone system. a toll assessing device. means for controlling said device, a Wheatstone bridge. other means for an balancing said bridge for controlling said 5 device through the medium of said first means. said first means including a circuit for said device, a source of potential in said circuit. a source of potential. for boosting the first potential in said circuit to control said device. a line a sociated With said device. a. trunk line. an automatic switch for connecting said line and trunk. a lousy test circuit for said trunk. another line and another switch having access to said trunk.

said trunk and said bridge using conductors in common. the circuit for said device and the busy test circuit having a conductor in common.

5. In a telephone system, a toll assessing 66 device, means for controlling said device, a

l vhcatstone bridge. and manually controlled means for unbalancing said bridge for controlling said device through the medium of said. first means.

6. In a telephone system]. a toll assessing device. means for controlling said device. a W'heatstone bridge. manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device. a source of potential. in said circuit. and a source of potential for boosting the first potential in said circuit to control said device.

7. In a telephone system, a toll assessing device. means for controlling said device. a Vheatstone bridge. manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means. said first means includin a. circuit for said device. a source of potential in said circuit. a source of potential for boosting the first potential in said circuit to control said device. and an impulse sender for controlling the application of said liiooster potential to said circuit.

8. In a telephone system, a toll assessing device. means for controlling said device. a Whcatslone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device. a source of potential in said circuit. a source of potential for boosting the first potential in said circuit to control said device. a line associated with said device. a trunk line. an automatic switch for connecting said line and trunk. a. busy test circuit for said trunk. another line and. another switch having access to said trunk, said trunk and said bridge using conductors in common. the circuit for said device and the busy test circuit having a conductor in common.

9. In a telephone system, a line, a toll assessing device associated With said line, means for controlling said device. another line, means for connecting said two lines, a subscribers telephone station for the second line. a IVheatstone bridge, and means for unbalancing said bridge for controllin said device through the medium of sai first means. said first means including a circuit for said device controlled by said second means.

10. In a telephone system, a line, a toll assessing device associated with said line. means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line. a heatstone bridge, means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a. circuit for said device controlled by said second means, a source of 1 ,sospss potential in said circuit, and a source of potentialfor boosting said first potential in said circuit to control said device.

11. In a telephone system, a line, a toll assessin device associated with said line, means or controlling said "device, another line, means for connectin said two lines, a subscribers telephone station for the second line, a VVheatstone bridge, means for unbalancing said bridge for controlling said device through. the medium of said first means said firstme ans includin a circuit for sai. device controlled by sait l second means, a source of potential in said circuit, a source of potential for boostingsaid first otential in said circuit tocontrol said device, and an impulse sender for controllingthe application of said booster potential to said circuit.

12. In a telephone system, a line, a toll assessin device associated with said line, means or controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a Wheatstone bridge, means for unbalancin said bridge for controlling said device t rough the medium of said first means, said first means including a circuit for said device controlled by said second means, a line associated with said device, a trunkline', an automatic switch *for'connecting said line and trunk, a bus test circuit for said trunk, another line an another switch having access to said trunk, said trunk and said bridge using conductors in common,'the circuit for said device and the busy test circuit having a conductor inco-mmon.

13.'In a telephone system, a line,a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, and manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuitfor said device controlled by said second means.

14. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subsbribers telephone station for the second line, a Wheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium, of said first means, said first means including a circuit for said device controlled by saidsecond'means, a source of potential in said'circuit, and a source of potential for boosting saidfirst potential in said circuit to controlsaid device.

15; In a telephone'system, a line, a toll assessin device associated with said line, means for controlling said device, another line, means for connecting said two lines, a

subscribers telephone station for the second line, a Wheatstone bridge, manually conbooster" potential to said circuit.

16. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a lVheatstone bridge, manually controlled means for unbalancin said bridge for controllin said device t rough the medium of said %rst means, said first means including a circuit for said device controlled by said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common.

17. In a telephone system, a line, a toll assessing device associated with said line means for operating said device, another lineymeans forconnecting the two lines, a subscribers telephone station for said second line, a signal for said telephone controlled by the subscriber on said first line, anoperator, a signal for said operator controlled by said second subscriber when answering said signal, a VVheatstone bridge, and means controlled by said operator for un'balancing said bridge for operating said device through the medium of said first means when the second subscriber signals said operator.

18. In a telephone system, a line, a toll assessing device associated with said line, means for operating said device, another line, means for connecting the two lines, a subscribers telephone station for said second line, a signal for said telephone controlled bythe subscriber on said first line, an operator, asignal "for said operator controlled by said second subscriber when answering said first signal, a VVheatstone bridge, means controlled-by said operator for unbalancing said bridge for ope'ratinu said device through the medium of said first means when the secondsubscriber signals said operatoi, said first means including a circuit for said device, a source of potential in said circuit, and a source of potential for boosting the first potential in said circuit to control said device.

19. In a telephone system, a line, a toll asscssin device associated with' said line, means or operating said device, another line, means or connecting the two lines, a subscriber's telephone station for said second line, a signal for said telephone controlled by the subscriber on said first line, an operator, a signal for said operator controlled by said second subscriber when answering said first signal, a Wheatstone bridge, means controlled by said operator for unbalancing said bridge for operating said device through the medium of said first means when the second subscriber signals said operator, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, and an impulse sender for controlling the application of said booster potential to said circuit.

20. In a telephone system, a line, a toll assessing device associated with said line, means for operating said device, another line, means for connecting the two lines, a subscribers telephone station for said sec- 0nd line, a signal for said telephone controlled by the subscriber on said first line, an operator, a signal for said operator controlled by said second subscriber when answering said first signal, a Wheatstone bridge, means controlled b said operator for unbalancing said bridge or operating said device through the medium of said first means when the second subscriber signals said operator, said first means including a circuit for said device, a source of otential insaid circuit,asource ofpotential orboosting the first potentialin said circuit to control sald device, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch havin access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the :busy test circuit having a conductor in common.

21. In a telephone system, a line, a toll assessin device associated with said line, means oroperating said device, another line, means for connecting the two lines, a subscribers telephone station for said second line, a si nal for said telephone controlled by the su criber on said first line, an operator, a signal for said operator controlled by said second subscriber when answering said signal, a Wheatstone bridge, and manual means controlled by said operator for unbalancing said bridge for operating said device through the medinm of said first means when the second subscriber signals said oporator.

22. In a telephone system, a line, a toll assessing device associated with said line,

means for operating said device, another line, means for connecting the two lines, a subscriber-s telephone station for said second line, a signal for said telephone controlled by the subscriber on said first line, an operator, a signal for said operator controlled by said second subscriber when anwering said first signal, a heatstone bridge, manual means controlled by said operator for unbalancing said bridge for operating said device through the medium of said first means when the second subscriber signals said operator, said first means including a circuit for said device, a source of potential in said circuit, and a source of potential for boosting the first potential in said circuit to control said device.

23. In a telephone system, a line, a toll assessing device associated with sand line, means for operating said device, another line, means forconnecting the two lines, a subscribers telephone station for said second line, a signal for said telephone controlled by the subscriber on said first line, an operator, a signal for said operator controlled by said second subscriber when answering said first signal, a Wheatstone bridge, manual means controlled by said operatorforunbalancing said bridge for operating said device through the medium of said first means when the second subscriber signals said operator, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuitto control said device, and an impulse sender for controlling the application of said booster potential to said circuit.

24. In a telephone system, a line, a toll assessing device associated with said line,

means for operatingsaid device, another line,

means for connecting the two lines, a subscribers telephone station for said second vline, a signal for said telephone controlled .by the subscriber on: said first line, an operator, a signal for said operator controlled by said second subscriber when answering said first signal, a \Vheatstone bridge, manual ,means controlled by said operator for unbalancing said bridge for operating said do ,vicethrough the medium of said first means when 1 the second subscriber si ials said operator, said first means inclu ing a circuit for'said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to con- -trol said device a line associated with said 'device,-a trunk line, an automatic switch tor connecting said line and'tr'unk, a lousy test circuit for saiditrunk, another line and an other switch havingaccessto said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in commonn-w w l subscribcristelephone station for the second line, a Vvheatstone bridge, "and means for unbalancing said bridge for controllin said device throu h' the medium of sai first means, said rst means including a circuit for said device controlled by said second means, said second means including a leg of said bridge.

26. In a telephone system, a line, atoll assassin device associated with said line, means or controlling said device, another line, means forconnecting said two lines, a subscribers telephoneistation for the second line, a W'heatston'e' bridge, means for un balancin said bridge for controlling said 'device tirou h the medium of said first means, said rst means including a circuit for said device controlled by saidsecond means, a source of potential in said circuit, and a source of potential for boosting said first potential in said circuit to control said device, said second means including a leg of said bridge:

27;In a telephone'system, a line, a toll assessing device associated with saidline,

means for controlling said device, another line, means for connectin' said two lines,-a subscribers telephone station for the second line, a Wheatstonebridge, means for unbalancing said bridge for controlling said device through the medium of said first subscribers telephone station for'the second line, a Wheatstone' bridge, means for unbalancin' said bridge for controlling said device t rough the medium of said first means, said first means including a circuit for said device controlled by said second means, a'line associated with said device, a trunk line, an automatic switch for connecting Said line and trunk, a busy test circuit for said trunk, another line and another switch having' ;access to said trunk, said trunk and said b rti'dge'usingi conductors in common, the circuit for said device and the busy test circuit having aconductor in common, said second means including a leg of said bridge I 29. In a telephone system, a line, a toll assessin device associated with said line, means or controlling said device, another line, means for connecting said two lines, a subscribe'rs telephone station for the second line, a W'heatstonc bridge, and manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means includi'n a circuit for said device controlled by said second means, said second means including a leg of said bridge.

30. In a telephone system, a line, a toll assessingdevice associated with said line, means for controlling saiddevice, another line,-means forconnectling said two lines, a subscribers telephonestation for the second line, a Wheatstone bridge, manually controlled means for unbalancing said bridge for controllin said device through the medium of said rst means, said first means includin' a circuit for said device controlled by sai second means, a source of potential in said circuit, and a source of potential for boosting said first potential in said circuit to control said device, said second means including a leg of said bridge.

31. In a telephone system, a line, a toll assessing deviceassociated with said line, means for controlling said device, another line, means forconnecting'saidtwo'lines, a subsci-ibers telephone station :tor the second line, a eatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium'of said first means, said first means including a circuit for said device controlled by said second means, a source of potential in said circuit, a source of potential for boosting said first potential in said circuit to'control'said device, and an impulse sender for controlling the application of said booster potential to said circuit, said second means including a leg: of 's'aid'br'idge.

32. In a telephone system, a line, a toll assessing device associated with said line, means :for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a Wheatstone bridge, manually controlled means for, unbalancing said bridge for controlling said device through' the me dium of said first means, said first means includinga circuit for saiddevice controlled by said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for saidtrunk another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuitfor said device and the'busy test circuit having a condoctor in common, said second means including a leg of said bridge.

33. In a telephone system, a line, a toll assessingdevice associated with said line,

means for controlling said device, another line, means for connecting said two lines, a snbscribers telephone station for the second line, a lVheatstone bridge, means for un- 5 balancing said bridge for controlling said device through the medium of said iiist means, said first means including a circuit for said device controlled by said second means, said second means including a leg of said bridge, said second means including also a progressively movable switch between said bridge and the called line, and means for sending impulses over said leg for operating said switch.

34. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, means for unbalancin said bridge for controlling said device t rough the medium of said first means, said first means including. a circuit for said device controlled by said second means, a source of potential in said circuit, a source of potential for boosting said first potential in said circuit to control said device, said second means including a-leg of said bridge,,said second. means including also a progressively movable switch between said bridge and the called l-1Iie,arid means for sending impulses over said leg for opera i g id witch, e a H 35. In a telephone system, a line, atoll assessing device associated with said line, means for controlling said device, another ,line, means for connecting said two lines, a subscribers telephone station for the second line, a VVheatstone bridge, means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controll d by 'sald lseoond means, a source of poteni ialin said ;.eae 1ii, a source of; potential for boosting said first potential in saidflcircuit, iocoiitrolfsaid device, an impulse sender for controlling the I; Hi" l "'l"lli fi 'l".m

applicat on ofsaid boosterpptent al to sa circuit, sa d second means including1 a leg of said bridge, said second meaiis inc u'diiig also a progr ively movable switch between S id bridge amine calledl'ine, ans meaiis for sending impulses over said leg {emperating said switch. l I l I a 36, In a telephoneisys tem, line, a toll assessin device associatedwith said line, views For vl ies id e; ath r li ans s whee s en tire i e a ii eribe ht ln wue stat stic the e ond ,q' i, yi i w,

l tstcae budge, means um ilees ngac d fiedtisnwfiidli S id ew t rone ai s issue of saidr is macs, said 'first a d me ns, a

l w peevw lee a a I isas seek Ime i? ll i t}, ,v mv t ,ior; sa d cri i 1Q di i i d ""1 5 .3%}... g

trolled means for unbalancing said .an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said second means including a leg of said bridge, said second means including also a progressively movable switch between said bridge and the called line, and means for sending impulses over said'leg for operating said switch.

37. In a telephone system, a line, a toll assessin device associated with said line, means .or controlling said device, another line, means for connecting said tWo lines, a subscribers telephone station for the second line, a VVheatstone bridge, manually con trolled means for unbalancing said bridge for controllin said device through the medium of said rst means, said first means ineludin acircuit for ,Sctld device controlled by sait second means, said second means includinga leg ofsaid bridge, said second means including also a progressively mov able switch between said bridge and the called line, and means for sending impulses :over, said leg for operating said switch.

38. In atelephone system, aline, a toll assessin device: associated with said line,

,means or controlling said device,. another l ne, means fo connecting said two lines, a sub i rtel ghaue s ation ifqr the s cond con- ;l n @Wlmats he bri ge manually for controllin said device through the medium of said rstmeans, said first means ,including a circuit; for said device controlled by said second means, a source of potential in said circuit, a source of potential for boosting said first potential in said circuit ,to control saiddevice, said second means in- 1 Ans; a I eg, af s id b d e s s n means including also a progqessive y; m0?!- ;able, switch bg tvween said lbr dge and. the ca l d i m n mea s r edin -imp l e 0W1, Said leg ,fpn operaiia gsmd switch, a a

9, 11 a. e phone/system, & lines v1 iassessiu device associated with-sald line, means, or controlling said device, another line, means for co mecting said two lines, 9. subscribers telephone station tor the second line, a heatstone lori ge, manually controlled ;means for unbaancing said bridge for controlling; said deyice through the meiv a Qf i are messed fir flms asin: draws a v it r sai aris cqi t ll lav aid 8 99 ,vm neaas ea 6 flete t a 4 c eal, isr vit s urce, b' Pe al, r

P eves sai assailed a a fa a o .7 a

3m a s6 ,s'eiidr' for cen al sap .i ev e i H 5 l 1 H uwiv y need es lite urina es at id b we potential ,sa d plrcuit said second means inclu'dii' g a leg of "s zii d br idg, said se aa avl e ese se acces es}? a able switch between said bridge and the called line, and means for sending impulses over said leg for operating said switch.

40. In a telephone system, a line, a toll assessin device associated with said line, means i br controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a 'heatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said second means includ ing a leg of said bridge, said second means including also a progressively mo able switch between said bridge and the called line, and means for sending impulses over said leg for operating said switch.

41. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a Wheatstone bridge, and means for unbalancing said bridge for controlling said device through the medium of said first means. said first means including a circuit for said device controlled by said second means, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

42. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a Wheatstone bridge, means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a source of potential in said circuit, and a source of potential for boosting said first potential in said circuit to control said device, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

43. In a telephonesystem, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, means for unbalancing said bridge for controllin" said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a source of potential in said circuit, a source of potential for boosting said first potential in said circuit to control said device, and an impulse sender for controlling the application of said booster otential to said circuit, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

44. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, means for unbalancing said bridge for controllin said device through the medium of sai first means, said first means including a circuit for said device controlled by said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

45. In a telephone system, a line, a toll assessing device associated with said line. means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a VVheatstone bridge, and manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge also provided with means for placing said device under the control of said bridge.

46. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a source of potential in said circuit, and a source of potential for boosting said first potential in said circuit to control said device, said second means eluding a leg of said bridge, said means incl riding also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

$7. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line. means for connecting said two lines, a subscriber-s telephone station for the second line, a Vheatstonc bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a source of potential in said circuit, a source of potential for boosting said first potential in said circuit to control said device, and an impulse sender for controlling the application of said booster potential to said circuit, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge. said bridge provided with means for placing said device under the control of said bridge.

49. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribcfis telephone station for the second line. a \Vlvatstone bridge. manually controlled means for unbalancing said. bridge for controlling said device through the medium of said first means, said firstmeans including a circuit for said device controlled by said second means, a line associatcd with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunh, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said second means including a leg of said bridge, said means including also a progressively movable switch between the first line and said bridge, said bridge provided with means for placing said device under the control of said bridge.

+9. in a telephone system. a toll assessing device associated with a line, means for controlling said device, a plurality of "hcatstone bridges, and means for unbalancing any one of said bridges for controlling said device through the medium of said first means.

50. In a telephone system, a toll assessing device associated with a line, means for controlling said device, a plurality of Wheatsto-ne bridges, means for unbalancing any one of said bridges for controlling said device through the medium of said first means, and a progressively movable switch controlled over said line for placing said device under the control of one of said bridges.

51. In a telephone system, a toll assessing device associated with a line, means for controlling said device, a plurality of \Vheatstonc bridges, means for unbalancing any one of said bridges for controlling said device through the medium of said first means, a progressively movable switch controlled over said line for placing said device under the control of one of said bridges, and means associated with each bridge for controlling said device to assess a diil'erent toll.

52. In a telephone system, a toll assessing device associated with a line, means for operating said device, Wheatstoue bridges divided into groups, means for nnbalancing any one of said bridges for controlling said device through the medium of said first means, and a progressively movable switch controlled over said line for electing any one of said groups of bridges for placing said device under the control of any one of the bridges in the elected group.

53. In a telephone system, a toll assessing device associated with a line, means for operating said device, \Vheatstone bridges divided into groups, means for unbalancing any one of said bridges for controlling said device through the medium of said first means, a progressively movable switch controlled over said line for electing any one of said groups of bridges for placing said device under the control of any one of the bridges in the elected group, and means associated with each bridge in the elected group for controlling said device to assess the same toll. 54. In a telephone system, a toll assessing deyice associated with a line, means for operating said device, \Vheatstone bridges divided into groups, means for unbalancing any one of said bridges for controlling said device through the medium of said first means, a progressively movable switch controlled over said line for electing any one of said groups of bridges for placing said device under the control of any one of the bridges in the elected group, means associated with each bridge in the elected group for controlling said device to assess the same toll.

55. In a telephone system, a toll device associated with a line, an operating circuit for said, device, a plurality of automatic circuit controllers associated with said device, each having a progressively movable element and each controlling the device to assess a different toll, said operating circuit closed through said element.

56. In.a telephone system, a toll device associated with a line, an operating circuit for said device, a plurality of automatic circuit controllers associated with said device, each having a progressively movable element and each controlling the device to assess a diilierent toll, said operating circuit closed through said element, a called line, means for connectingthe two lines, a balance circuit associated with each one of said controllers, a signal associated with the called line, means for operatingsaid signal from said called line, and means for unbalancing one of said circuits after said signal is operated for operating said toll device.

57. In a telephone system, a toll device associated with a line, an operating circuit for said device, a plurality of automatic circuit controllers associated with said device, each having a progressively movable element and each provided with means for operating said device a number of times each time the controller is brought into operation to assess a toll, a called line, means for connecting the two lines, a balance circuit as sociated with each one of said controllers, a signal associated with the called line, means for operating said signal from said called line, and means for unbalancing one of said circuits after said signal is operated for operating said toll device.

58. In a telephone system, a toll device associated with a line, an operating circuit for said device, a plurality of automatic circuit controllers associated with said device, each having a progressively movable element and each provided with means for op erating said device a number of times each time the controller is brought into operation to assess a toll, an automatic switch for automat'cally connecting said line with, any one 0 said circuit controllers, a called line, means for connecting the two lines, a balance circuit associated with each one of said controllers, a signal associated with the called line, means for operating said signal from said called line, and means for unbalancing one of said circuits after said signal is operated for operating said toll device.

59. In a telephone system, a toll assessing device associated with a line, an operating circuit for said device, an automatic circuit controller associated with said device, said controller having a progressively movable element and provided with means for op crating said device a number of times each time the controller is brought into operation to'assess a toll, said operating circuit closed through said element, another line, means for connecting the two lines, a signal under the control of said second line, a balance circuit associated with said controller, and means for unbalancing said circuit after the said signal is operated to bring said controller into operation 60. In a telephone system, a toll assessing device associated with a line, an operating circuit for said line, means for extending a connection to any one of a plurality of lines, automatically controlled equipment having a progressively movable element associated with said device, and means for starting said equipment after connection is extended to the called line for variably operating said device depending upon the line to which connection is extended, said operating circuit closed through said progressively movable element.

61. In a telephone system, a measured service device associated with a line, an operating circuit for said device, means for extending a connection from said line to any one of a group of lines, automatic circuit controlling equipment having a pro gressively movable element associated with said group of lines for controlling the operation of said device, said equipment arranged for variably operating said measured service device whereby the device is operated to assess one toll if the first line is connected to one line of the group, and operated to assess a diiierent toll if the line is connected to another line of the group, said operating circuit closed through said element.

62. In a telephone system, a toll assessing device, means for controlling said device, a W'heatstone bridge, other means for unbalancing said bridge for controlling said device through the medium of said first means. said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said de vice, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said conductor being one of the con ductors of said trunk.

63. In a telephone system, a. toll assessing device, means for controlling said device, :1 Vheatstone bridge, other means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device, a smlrce of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said de vice. an impulse sender for controlling the application of said boosterpotential to said circuit. a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common. the circuit for said device and the busy test circuit having a conductor in common.

64. In a telephone system, a toll assessing device, means for controlling said device, a \Vheatstone bridge, other means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, an impulse sender for controlling the application of said booster potential to said circuit. a line associated with said device, a trunk line. an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test ciruiit having a conductor in common. said conductor being one of the conductors of said trunk.

65. In a telephone system, a toll assessing device, means for controlling said device, a \Vheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, a line associated with said device, a. trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk. said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common.

66. In a telephone system, a toll assessing device, means for controlling said device, a \Vheatstone bridge. manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said do vice and the busy test circuit having a conductor in common, said conductor being one of the conductors of said trunk.

67. In a telephone system, a toll assessing device, means for controlling said device, a Wheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means includin a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, an impulse sender for controlling the application of said booster potential to said circuit, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk' and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common.

68. In a telephone system, a toll assessing device, means for controlling said device, a Wheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device, a source of potential in said circuit, a source of potential for boosting the first potential in said circuit to control said device, an impulse sender for controlling the application of said booster potential to said circuit, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said conductor being one of the conductors of said trunk.

69. iIn a telephone system, aline, a tell assessing device associated with said line,means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a \Vheatstone bridge, means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled by said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said trunk and said device using conductors in common.

70. In a telephone system, a line, a toll assessing device associated with said line, means for controlling said device, another line, means for connecting said two lines, a subscribers telephone station for the second line, a Wheatstone bridge, manually controlled means for unbalancing said bridge for controlling said device through the medium of said first means, said first means including a circuit for said device controlled lby said second means, a line associated with said device, a trunk line, an automatic switch for connecting said line and trunk, a busy test circuit for said trunk, another line and another switch having access to said trunk, said trunk and said bridge using conductors in common, the circuit for said device and the busy test circuit having a conductor in common, said trunk and said device using conductors in common.

71. In a telephone system, a meter, a circuit for operating said meter, a circuit closer for controlling said circuit, a \Vheatstone bridge, and means for unbalancing said bridge to operate said circuit closer.

72. In a telephone system, a measured service device, a circuit for operating said de vice, a progressively movable circuit closer for controlling said circuit, a Wheatstone bridge, and means for unbalancing said bridge to operate said circuit closer.

73. In a telephone system, a line, a toll device individual to said line, means for controlling said device, a trunk line, a Wheatstone bridge individual to said trunk, means for connecting said line and trunk, and means for unbalancing said bridge to operate said device through the medium of said first means.

74. In a telephone system, a plurality of lines, a toll assessing device for each line, a Wheatstone bridge common to said lines, means for connecting any one of said lines with said bridge, and means for unbalancin said bridge to operate said device.

%5. In a telephone system, a plurality of lines, a toll assessing device for each line, a Wheatstone bridge common to said lines, an automatic switch for connecting any one of said lines with said bridge, and means for unbalancing said bridge to operate said device.

76. In a telephone system, a plurality of lines, a toll assessing device for each line, a VVheatstone bridge common to said lines, means for connecting any one of said lines with said bridge, and manually controlled means for unbalancing said bridge to operate said device.

.for said line,

77. In a telephone system, a plurality of lines, a toll assessing device for each line, a Wheatstone bridge common to said lines, an automatic progressively movable switch for connecting any one of said lines with said bridge, and means for unbalancing said bridge to operate said device.

78. In a telephone system, a line, a toll assessing device for said line, a trunk line, an automatic switch for extending a connection from said line, and an operating circuit for said switch and for said device including the two sides of said trunk line in parallel.

79. In a telephone system, a line, a toll assessing device for said line, a trunk line, an automatic switch for extending a connection from said line, an operating circuit for said switch including the two sides of said trunk line in parallel, and means controlled over said operating circuit for causing said device to register a predetermined number of times.

80. In a telephone system, a line, a toll a sessing device for said line, a trunk line, an automatic switch for extending a connection from said line, an operating circuit for said switch including the two sides of said trunk line in parallel, and automatic means controlled over said operating circuit for causing said device to register a variable number of times.

81. In a telephone system, a line, a meter for said line, a trunk line, an automatic switch for extending a connection from said line, a simplex circuit superimposed on said trunk line, means for operating said switch over said simplex circuit, a Wheatstone bridge for controlling the operation of said meter, one arm of said bridge including said simplex circuit.

82. In a telephone system, a line, a meter a trunk line, an operators position, means for extending a connection from said line over said trunk line to said opcrators position, a simplex circuit includ ing the two sides of said trunk line in parallel, and automatic means controlled by the operator over said simplex circuit for operating said meter to register a call.

83. In a telephone system, a line, a meter for said line, a trunk line, an operators position, means for extending a connection from said line over said trunk line to said operators position, a simplex circuit includ ing the two sides of said trunk line in parallel, and automatic means controlled by the operator over said simplex circuit for operating said meter a predetermined number of times to register a call.

84. In a telephone system, a line, a meter for said line, a trunk line, an operators position, means for extending a connection from said line over said trunk line to said 

